The present disclosure relates to a wireless communication device and a power receiving device. Particularly, the disclosure relates to the wireless communication device and the power receiving device capable of performing communication and the like while obtaining sufficient power even when communication is performed in a state in which antennas of transmission-side and receiving-side wireless communication devices make contact with each other closely.
In related arts, an NFCIP-1 (Near Field Communication Interface and Protocol-1) standard is provided as an international standard of near-field wireless communication. A reader/writer and an IC card complying with the NFCIP-1 standard are broadly used for individual authentication, electronic money payment and the like.
In data communication using a type complying with the NFCIP-1 standard (hereinafter, referred to as an “NFCIP-1 type”), a passive communication mode and an active communication mode by 13.56 MHz electromagnetic induction coupling are prescribed. In the passive communication mode, a non-modulated carrier signal is transmitted from the reader/writer to the IC card. The IC card modulates the transmitted non-modulated carrier signal in accordance with data to be transmitted. The reader/writer obtains data transmitted from the IC card by performing demodulation and the like of the modulated carrier signal. Accordingly, in the passive communication mode, communication is performed without generation of the carrier signal by the IC card itself. Also in the passive communication mode, power generation is performed by using the carrier signal transmitted from the reader/writer and operations of the IC card are performed by using the generated power.
On the other hand, in the active communication mode, the IC card itself generates the carrier signal, modulates the generated carrier signal in accordance with data to be transmitted, then, transmits the signal. The reader/writer performs demodulation and the like of the modulated carrier signal, thereby obtaining data transmitted from the IC card. Accordingly, in the active communication mode, for example, as in JP-A-2005-323264 (Patent Document 1), processing of generating the carrier signal, modulating the generated carrier signal in accordance with data to be transmitted and transmitting the modulated carrier signal is performed by providing a power supply unit using a primary battery or a secondary battery in the IC card and supplying power to respective units of the IC card from the power supply unit.
In the case of the passive communication mode, it is assumed that main applications of the IC card used for the near-field wireless communication are individual authentication (for example, at an entrance gate), electronic money payment (for example, at a vending machine” and the like, therefore, the IC card is designed so that communication stability can be obtained maximally when the IC card is carried by a human hand, for example, when the reader/writer and the IC card is several centimeters apart from each other. Accordingly, it is difficult to obtain stable power in conditions different from the case in which the card is operated by a human hand. For example, when communication of video contents or audio contents is performed by using the reader/writer and the IC card, the IC card is placed on the reader/writer in a state of touching the reader/writer, therefore, it is difficult to obtain stable power.
Additionally, it is necessary to provide the power supply unit using the primary battery or the secondary battery in the active communication mode, therefore, when the remaining amount of the battery is reduced, battery change or charging by connecting the IC card to a charger is necessary.
Thus, it is desirable to provide a wireless communication device and a power receiving device capable of performing communication and the like while obtaining sufficient power even when antennas of transmission-side and receiving-side wireless communication devices are in a close contact state.